Protective shield



Dec. 19,1944. M; R. am.; *2,365,328

PROTECTIVE 'SHIELD Filed Dec. 10, 1941 Patented Dec. 19, 1944 T; OFFICE PROTECTIVE suman Millard n. Bell, Los Angeles, cam., assignor to The B. F. Goodrich Com a corporation of New Y pany, New York, N. Y., ork

Application December 10, 1941, Serial No. 422,343

4 Claims. This invention relates to means for protecting parts of aircraft and other structures which are exposed in air flow to icing conditions. The invention is useful in preventing the accumulation of ice and in reducing or eliminating contact of stones, dirt, -oil and other foreign matter with such parts, and it is advantageous especially in preventing the accumulation of ice on and in air scoops, including the air intake manifolds of aircraft.

The problem presented heretofore by the 'formation of ice on and in the air intakes of aircraft has been dimcult of solution, particularly lsince the turning vanes desirable in the scoop for providing smooth air-ow to the carburetor'have in many cases supported ice and permitted bridging of the ice over the vanes and over the mouth of the scoop.

Prior expedients utilizing. anti-icing liquids have had the objection of polluting the air, and expanslble ice-removing devices alone have 'not been entirely satisfactory owing to consequent restricting and disturbing effects on the air ow into and through the scoop.

The chief objects of the present invention are to provide means for protecting the exposed portions of air intake manifolding from the accumulation of ice and from the entrance of dirt, Y

oil and objectionable amounts of Water and other foreign matter; to provide means for preventing the accumulation of ice in and on the carburetor air scoops of aircraft, while permitting adequate air-flow for proper carburetion;

to provide for a minimum of aerodynamic drag, and to provide for simplicity and economy of manufacture.

These and further objects will be apparent from the following description, reference being had to the accompanying drawing 'in which:

Fig. l is a perspective view of a portion of an airplane having protective means mounted thereon constructed in accordance with and embodying the invention.

Fig. 2 is a plan view of the protective means on an enlarged scale. Y

Fig. 3 is a section taken along the line 3 3 of Fig. 2.

Fig. 4 is' a viewin longitudinal section of a modified construction.

Fig. 5 is a plan view of the modified construction of Fig. 4, parte being broken away.

In the illustrative embodiment of the drawing, a protective shield III of streamline shape is mounted forwardly kof and is spaced, preferably adjustably, from air intake opening Il of a carburetor air scoop I2. As shown in Fig. 1, the air scoop I2 is mounted on top of a motor nacelle I3.of a wing I4 of an airplane, indicated generally at I5. Alternatively, the air scoop I2 may be lmounted at any other suitable position on the nacelle I3 or aircraft and the protective shield I provided forwardly of the scoop I2 and in substantially the same relative position with respect thereto.

'I'he air scoop I2, in the form shown in the drawing, comprises a tubular portion I6 for conducting air to the carburetor of a motor of the airplane I after the air enters the opening II from the airstream. Turning vanes I'I, I'I provide for smoothness of air-now, and a screen I8 c or other suitabley filtering means assists in freeing the carburetor-bound air of foreign matter.

The protective shield- I0 may be mounted .on the airplane in any suitable manner, as for example. adjustably by means of screws I9, I9 in slots 20, 20 in a projecting flange portion 2l of the shield I0 as shown, the slots 20, 20 permittingA adjustment of the distance between the shield I0 and the opening II of the air scoop I2.

The forwardly-projecting surface 22 of the streamline shield I Il is preferably provided of an area such that the entire opening II of the air intake I2 is shielded. The rounded surface 22 of the shield III provides an area for the impingement of water and snow, and also for the impingement and deflection of dirt, stones, oil and other foreign matter. Whereas water kand snow heretofore have formed ice on the scoop I2, in some cases completely closing the opening I I in the scoop I2, the dirt, oil and other foreign'- 1- matter have entered the air intake and.have

mixed objectionably with the air supplied to the carburetor or clogged the air filter I8 in the intake manifolding I6, the shield I0` serving to guard against this.

I provide that accumulations of ice will be on the shield I0 where its presence will not be harmful to the operation of aircraft and the flow of air to the air scoop I2 will diminished.

Particles of water, dirt and the like not deposited on the shield will be carried over and past thecritical area of the o peningvII of lthe scoop I2, without appreciably interfering with the cleanness of the aerodynamic contours of the aircraft. In this action the inertia of such moisture and particles assists them in passing the scoop, and good results in this respect have be substantially unbeen obtained with a shield having lateral diample, by means of mensions slightly greater than those of, the scoop.

Rearward surfaces 22a, 22a of the shield l0 of the shape shown, but winch may be constructed of any other suitable streamline shape, permit free flow of air to the scoop i2, the air having greatly reduced moisture content as well `as greatly reduced content of other undesirable foreign matter. It has yalso been found that the streamlined shield construction of the invention provides for a more uniform flow of air into the air scoop, layers of entering air from wall to wall of the scoop being of more even velocity of flow. The action of diverting moisture and other particles from the scoop while nevertheless providing more uniform flow of air into the scoop, is contributed to by the preferred streamlined shape shown, wherein the rearward side surfaces 22a.' 22a taper back to a rearmost surface that rises generally 'vertically to substantially the top of the shield, see especially Figs. 2 and 3, so that the top does not taper downward toward the rear. Thus the flow of air into the scoop is chiefly from the sides 22a, 22a of the shield and is not disturbed by downward flow of air that would occur if the top of the shield were tapered downward toward the rear.

A suitable antifreeze liquid may be fed into the protective shield i0, if desired, to minimize the accumulation of ice on the shield, as for exa suitable feeding tube 23 of the shield as shown in Figs. 2 and 3, or by any other suitable means. A suitable drip strip 24 may be provided, if desired, to conduct inwardly toward the cowling of nacelle of the aircraft anti-freeze liquid or accumulations of water which may now along the surface of the shield so that such liquid will not be carried into the air-scoop. The air-scoop i2 is preferably provided with grooved portions at the front and sides to guide such liquids around the air-scoop I2 and away, as indicated at 12a in Fig. 3. n

The modified construction of Figs. 4 and 5 comprises an alternative shape of streamlined shield 25 more nearly in the shape of a tear-drop.v In these figures also the construction comprises an inflatable covering 26 mounted on the entering surface thereof for breaking-up accumulations of ice on the shield. The inatable covering 26 may be of any suitable construction, but preferably comprises an at the leading end inflatable tube 21 cen-` by air-flow past the shield.

trally ofthe entering surface of theshield 25'.

and connected by means of a .pipe member 28 to a source of inilating fluid (not shown).l A

permitting flow of air into escasas layer ofv elastic material v28 overlying the inflatable tube 21 and extending preferably over the entire entering surface` of the shield 25 and secured as Iby means of rivets or bolts back of the entering surface, as indicated at 30, In, is distorted'and stretched hen the tube 21 is inflated to break-up ice formations on the shield 25 and permit the removal of the broken ice The inflated positipn of the covering is indicated by broken lines in Fig. 4. 1

While I have described my invention with particular reference to the protection of carburetor airvscoops, features of the 'invention are applicable to the prevention of the accumulation of ice -on other elements similarly exposed to icing conditions.

Variations may be made without departing from the scope of the invention as it is defined by the following claims.

. I claim:

l. A shield for protecting an`air scoop, said shield comprising a, body of streamline form disposed in advance of the mouth of the scoop to shield the mouth from air-borne particles while the scoop around the streamline surface of the shield, and said streamline surface including a rounded frontal portion and side portions converging rearward to a rearmost portion extending vertically throughout substantially the vertical depth of the shield.

2. A shield as defined in claim l in which the maximum transverse dimensions of said body exceed slightly the corresponding dimensions of said -mouth to eclipse the mouth totally.

3. A shield as deilned in claim l comprising lip means on the surface thereof extending along the sides of the shield and rearwardly toward its base for conducting water on the shield away from the mouth of said scoop.

4. A shielded air scoop assembly comprising an air scoop, a shield therefor, said shield having a streamlined surface including a rounded frontal portion and side portions tapering rearward and overall transverse dimensions not substantially exceeding the corresponding dimensionsof the mouth of said scoop, and said shield being disposed in advance of said mouth at a position to deflect air borne particles into paths to the sides of the scoop so that their inertia prevent: their entrance into said mouth, while the shielc permits flow of air around the shield andintc said mouth.

MILLARD R. BELL.v 

